1. Technical Field
The present invention relates to a speech recognition device and a speech recognition method that, for example, recognize speech and respond or perform processing according to the recognition result. Furthermore, the invention relates to a semiconductor integrated circuit device that is used in such a speech recognition device and speech recognition method.
2. Related Art
Speech recognition is a technology that obtains a recognition result by analyzing an input speech signal and collating a feature pattern obtained as a result of the analysis with standard patterns (also referred to as “templates”) that are provided in a speech recognition database based on prerecorded speech signals. While option information in speech recognition generally exists in a speech recognition dictionary, updating the option information during execution of speech recognition processing is problematic because of the time taken to update the speech recognition dictionary.
As a related technology, JP-A-2008-15209 (para. 0009-0012, FIG. 1) discloses a speech recognition device that enables the recognition dictionary of each speech recognition processor to be updated efficiently, without interrupting the speech recognition service. This speech recognition device is described as being a speech recognition device for recognizing speech data received from a user terminal based on a recognition dictionary, including a recognition dictionary storage means in which the recognition dictionary is stored, a plurality of speech recognition processing means for reading out the recognition dictionary from the recognition dictionary storage means, updating a common dictionary area thereof by registering the recognition dictionary, and recognizing speech data based on this recognition dictionary, a speech recognition request reception means for, in response to a speech recognition request, causing one of the speech recognition processing means to perform recognition of speech data, and a dictionary update request reception means for, in response to a dictionary update request, selecting each speech recognition processing means at least once over a plurality of times, and sequentially causing the selected speech recognition processing means to update its recognition dictionary.
According to the speech recognition device of JP-A-2008-15209, each speech recognition processing means is selected for recognition dictionary updating at least once over a plurality of times and its recognition dictionary is updated, thus enabling the speech recognition device as a whole to update the recognition dictionaries of all the speech recognition processing means without interrupting the speech recognition service.
However, even if it thus becomes possible to update the speech recognition dictionary without interrupting the speech recognition service, in the case where a restriction is not placed on the collation range when collating feature patterns obtained by analyzing input speech signals with standard patterns, the number of combinations of feature patterns and standard patterns to be compared will be huge, leading to an increase in processing time, and the increase in possible vocabulary will conceivably make the determination more difficult and give rise to a fall in the recognition rate.
As a countermeasure to this problem, the recognition rate can conceivably be improved through restricting the number of combinations of feature patterns and standard patterns to be compared, by performing speech recognition in accordance with a preset scenario, for example, although in order to set the scenario, it is necessary to either incorporate the flow or the like of the scenario as program code or create program code for controlling an external speech recognition device in the CPU (central processing unit) in which the speech recognition software is installed. However, the program code has to be changed in the CPU when the scenario is changed, requiring much time and many man hours in changing and evaluating the program code, and the like. In view of this, it is an advantage of some aspects of the invention to enable setting, changing and the like of scenarios in speech recognition to be easily realized.